Squidtastic Voyage/That's No Lady - S4-E15
Audio problem: In "That's No Lady", Mr. Krabs throws a megaphone behind him, but there is no sound of it clattering after him throwing it.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", there is a place card on the table Mr. Krabs is sitting at. When he puts a sheet over the table, the spot where the card was, doesn't bulge.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Patrick has some type of glasses, which he takes off his face and holds in his hand. In the next shot, they disappear.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Spongebob has a tray with two lemonades and gives one to Patrick. In two shots, the tray and the two glasses of lemonade disappear.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "Squidtastic Voyage", Squidward drinks many bottles of soda to try and get Spongebob and Patrick out of his stomach. Two shots later, these bottles all disappear without anyone touching them.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In 'Squidtastic Voyage", Spongebob uses a remote to open the doors of the submarine. This remote disappears in the next shot.
Krabby Land / The Camping Episode - S3-E19
Continuity mistake: In "Krabby Land", Mr. Krabs is in his boat with Spongebob in front of the playground filled with children. After looking through a pair of binoculars, he drops them in front of the boat. However, in the next shot the binoculars are gone.
Mermaid Man and Barnacle Boy IV / Doing Time - S3-E1
Continuity mistake: In "Doing Time", Spongebob's entire face fills the chili bucket, but when he peeks out, his body is relatively smaller than the bucket.
Continuity mistake: In the episode "The Sewers of Bikini Bottom", Mr. Krabs is talking to the owners of the Krusty Krab Stadium and there are two pennants on the wall behind them. In a later shot through a window, there is only one pennant on the wall.
Continuity mistake: In "Patrick! The Game", the whole group is outside and Squidward rolls a die. The die disappears in the next shot.
Continuity mistake: In the episode "Patrick! The Game", Patrick puts on a surgeon mask. This mask eventually disappears in a later shot.
Continuity mistake: In "Patrick! The Game", Spongebob takes the rulebook and puts it off to the side. In the next shot, the book disappears.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: In "Mermaidman Begins", Mermaidman and Barnacleboy are running across a dock, about to jump into the sea. Next to them, on the right, there is a pelican sitting on a pillar. In the next shot at a different angle, the pelican is gone.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: In "Mermaidman Begins", the first time it shows Ernie microwaving the popcorn, there are 21 buttons on the microwave. In a later shot, there are now 24.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: In "Mermaidman Begins", the scientist experimenting on the ants knocks over the jar containing five ants. In the next shot, there are eight ants on the floor.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: In "Mermaidman Begins", the camera goes up one story to show a scientist. On the poster next to him, it shows various molecules and particles. In the next shot, the word "science" appears on the poster.
Karate Star - S8-E2
Continuity mistake: Spongebob is mopping the floor when a customer walks in the tell him about Patrick chopping everything. Two shots later, the mop and the water on the floor disappear.
Continuity mistake: Spongebob is looking up at the roots that are bouncing above him. In the first shot, there are only three above him. In the next shot, it shows more roots, with Spongebob standing under four.
A Flea in Her Dome / The Donut of Shame / The Krusty Plate - S5-E11
Continuity mistake: In "The Krusty Plate", Spongebob finds that one plate has a brown smudge on it. After an attempt to clean the plate, he lifts it up and the smudge is now a light shade of green.
Giant Squidward/No Nose Knows - S6-E7
Continuity mistake: In "Giant Squidward", Squidward goes to spray his wilting kelp with fertilizer and sets down a watering can right next to him. When the kelp goes back to normal in the next shot, the watering can disappears and is not seen again.
Answer: I believe this is the Season 6 episode "Spongicus".